Detections
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Mozilla Firefox ESR < 140.12

critical Nessus Plugin ID 321193

Synopsis

A web browser installed on the remote Windows host is affected by multiple vulnerabilities.

Description

The version of Firefox ESR installed on the remote Windows host is prior to 140.12. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-58 advisory.

 - Memory safety bugs present in Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151.
 Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. (CVE-2026-12327)

 - Use-after-free in the Networking: HTTP component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, and Firefox ESR 115.37. (CVE-2026-12291)

 - Incorrect boundary conditions in the Web Audio component. This vulnerability was fixed in Firefox 152 and Firefox ESR 140.12. (CVE-2026-12292)

 - Sandbox escape in the DOM: Navigation component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, and Firefox ESR 115.37. (CVE-2026-12295)

 - Sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 152 and Firefox ESR 140.12. (CVE-2026-12296)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Upgrade to Mozilla Firefox ESR version 140.12 or later.

See Also

https://www.mozilla.org/en-US/security/advisories/mfsa2026-58/

Plugin Details

Severity: Critical

ID: 321193

File Name: mozilla_firefox_140_12_esr.nasl

Version: 1.1

Type: Local

Agent: windows

Family: Windows

Published: 6/16/2026

Updated: 6/16/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2026-12327

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:mozilla:firefox_esr

Required KB Items: installed_sw/Mozilla Firefox ESR

Exploit Ease: No known exploits are available

Patch Publication Date: 6/16/2026

Vulnerability Publication Date: 6/16/2026

Reference Information

CVE: CVE-2026-12289, CVE-2026-12290, CVE-2026-12291, CVE-2026-12292, CVE-2026-12294, CVE-2026-12295, CVE-2026-12296, CVE-2026-12297, CVE-2026-12298, CVE-2026-12299, CVE-2026-12302, CVE-2026-12304, CVE-2026-12305, CVE-2026-12306, CVE-2026-12307, CVE-2026-12308, CVE-2026-12309, CVE-2026-12310, CVE-2026-12311, CVE-2026-12312, CVE-2026-12313, CVE-2026-12314, CVE-2026-12315, CVE-2026-12324, CVE-2026-12325, CVE-2026-12327, CVE-2026-12328, CVE-2026-12329, CVE-2026-12330